Carburetor



May 6, 1941. w. C. DUNN 2,240,497

V GARBURETOR` I Original Fld July 6, 1937 5 Sheets-Sheet 1 &

May 6, 1941,

W. C. DUNN v CARBURETQR 5 Sheets-Sheet 2 Original Filed July 6, 1957 .gil

aff/5555112915 w.y c. DUNN CARBURETOR May 6, 1941.

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Original Filed July 6, 1937 I lI /Z 'M I l May 6, 1941.

GARBURETOR l original Fuga July 6, 1937 5 Sheets-Sheet 4 May 6, 1941. y l w, C, DUNN 2, 24,497

cARBUREToR originalV Filed July e, 1937 5 sheets-shet 5 HI l||| 1u Hlv g a2 (Il "I I y Il' ls (o ma" I; g fg I I l Il' H a Gn l@ [l Il' K L9 l RO l n I" Y Q. 9X gq;

Patented May 6, 1941 unirse sri-iras are OFFICE luly 6, 1937. Serial No. 272,731

4 Claims.

. This application is a continuation of Aapplication Serial $153,119, filed July 6, 1937.

This invention relates to improvements in carburetors for internal combustion engines, and has for one of its objects to provide improved means for creating and maintaining the most desirable mixture proporticnsfor the varying demands of the engine to which the device is connected.

A further object is to provide in a carburetor of this character improved means whereby two different kinds of fuel may be employed and supplied so that the engine may be started and operated on one of the fuels, after which it may be run on a combination of the two fuels fed in pre'- deterrnined proportions, thereby resulting in an economical operation of the engine. l

Means are also provided whereby the engine may be run entirely on one of the fuels alone, if

desired.

' To the attainment of these ends and theaccomplishment of other new and useful objects as Jill appear, the invention consists inthe features of novelty substantially the construction, cornbination and arrangement ofthe several parts, hereinafter more fully described and claimed and shown in the accompanying drawings illustrating this invention, and in which Figure l is a vertical longitudinal sectional view of a carburetor of this character constructed in accordance with the principles of this invention and as taken on line I I, Figure 3, Figure 1 being on an enlarged scale.

Figure 2 is a detail horizontal sectional View `taken on line 2 2, Figure 1.

Figure 3 is a top plan view of the carburetor, with parts broken away.

Figure 4 is a horizontal sectional View taken on line 5 4, Figure l.

Figure 5 is a vertical sectional view taken on line 5 5, Figure 3, on an enlarged scale.

Figure G is a detail sectional view of aportion of the casing of the carburetor.

Figure 'l is a vertical sectional view taken on line 1 1 Figure 3.

Figure 8 is a vertical sectional view taken on line 8 8 Figure 3.

Figure 9 is a diagrammatic view of the system embodied in this invention.

Referrinor more particularly to the drawings,

the numeral I5 designates a casing of any size andY configuration and is provided with an air inlet opening it and a discharge outlet Il. The casing is adapted to be supported above the intake manifold and may be secured in position in the usual manner by means of fastening devices passing This application May 9, 1939,

(El. E61- 18) through suitable openings I8 in the base of the casing.

Within the casing is arranged a mixing chamber I9 which has communication with the outlet I l, and a throttle valve 2G controls the outlet.

The inlet I5 is controlled by means of a valve 2l pivotally mounted as at 22 and the valve is adapted to be moved about its pivot to open and close the inlet, automatically in a manner to be later described.

Arranged within the wall of the casing l5 is a passage 23 which has communication with the inlet opening l5, on the upper side of the valve 2l by means of a suitable opening 24-a, any number of which may be provided. The passage 23 leads around or to the other side of the valve 2l and is closed at its lower end. 'Ihe passage 23 at its lower end is provided with a bottom wall of inverted conical formation 24, the bottom being provided with outlet passages 25, any number of which may be employed.

The conical bottom24 of the passageV 23 is arranged in alinement with the inlet opening I6 and also arranged beneath and in alinement with Y the conical bottom 24 is a throat or tube 26 which terminates considerably short of the throttle valve 2li, and the inlet I6 has communication with the mixing chamber I9 through a suitable opening 21 which extends around the nozzle formed by the conical bottom 24 of the passage 23 and the tubular throat or passage 26.

This throat or tube 26 may be of any desired configuration and diameter and of any suitable length, andis'provided With an opening 23 in the top thereof, the wall of the opening tapering from the periphery of the tube toward the diametrio center of the opening to form a tapering or inclined surface of a substantial area about the opening The apex of the conical bottom 24 of the passage 23 projects into the opening in the end of the throat or tube and abuts the surface surrounding the top wall of the throat or tube. Within the surface of the conical portion of the opening there are arranged a plurality of channels 29 extending from the periphery of the surface toward and communicating with the openingZB in the upper end of the tube 26. These channels 29, any number of which may be provided, are spaced about the conical bottom 2 4 and the openings 25 are respectively arranged above the channels to form communications therewith so as to direct air which may enter the passage 23 from the inlet IS through the opening 24 a, into the channels 29 to be discharged into the throat or tube 26.

In the upper portion of the throat or tube 25 is arranged a circumferential channel which is divided by upright partitions 35, into two sections 3 |-32 which are out of communication with each other, and a closure plate or cap 33 is provi-ded for the channels, the tube and the cap plate being preferably removably secured in position by means of suitable fastening devi-ces 34.

Extending through the body of the throat or tube are passages 35--35 which are arranged on opposite sides of the partitions 3i? and form connections between the channels 29 and the respective portions 3 l-SZ of the channels so that when fuel is supplied to these channels, in a manner to be hereinafter described, the fuel therein, by reason of the air currents owing through the openings 25 in the bottom 24 of the passage 23, will be directed across the passages 35-35 into the throat or tube 26. This will entrain or atomize the fuel from the respective channels i-l2 into the channels 25 to be discharged into the throat or tube 25 and thence into the mixing chamber i9 where it will commingle with the being drawn .into the inlet opening i5.

If desired, the conical bottom 24 of the passage 23 may also be provided with an opening 31 in its apex to direct air into the throat or tube 25 between the incoming streams of fuel for better atomization thereof.

The external diameter of the throat or tube 25 is considerably .smaller than the internal diameter of the mixing chamber is and also terminates a considerable distance short of the bottom of the chamber.

Supported by the casing i5 is a fuel containing tank or reservoir 38 which may be oi any desired size and configuration and leading therefrom and vdisposed preferably on the interior of the chamber is a passage 39 having a discharge outlet 5i! that extends through the wall 4| that is disposed intermediate the tanlr'SB and the mixing chamber I9. A pipe 2 is connected by one end to the channel 5| and on its other end is a plug d5 for securing or ancho-ring the other end of the pipe or tube in communication with the passage 5. i

This pipe or tube 62 may be of any desired diameter Yand length and 'serves as a means whereby a liquid fuel, such for instance as gasoline, will be supplied from the tank`38 into the channel 3| to be atomized or entrained into the throat or tube 26.

'I'he passage 39 is preferably in the form of a chamber and seated at the upper end thereof is a member lili having an opening d5 therethrough to form communication between the reservoir 38 and the chamber 39 and through which opening 45 fuel will flow into the chamber to be delivered through the outlet d5 and thence through the pipe 42 to the nozzle.

A metering valve i3 of a tapered construction projects into the opening 45 and is movable longitudinally so as to vary the size of the opening 5 and thereby meter the fuel which is delivered to the Chamber 55.

The Valve 55 is operable, or moved longitudinally, under thel influence of a weight di which moves in a chamber i8 in the casing.

In the end of the weighted member i? is provided a circumferential recess i9 shaped to form a shoulder fail-o and a shoulder t9-b. The circumferential groove 69 is of a substantial width encompassing the member 41, and seated Within the groove or recess 59 is an annular member 4S-c of an external diameter only slightly less than the internal diameter of the chamber or cylinder 48 within which the end of the member 41 operates.

A disc lise is secured to the end of the member 1, preferably by means of a screw and co-operates with the shoulder 49a to prevent displacement of the annular member figc.

Any number of apertures or openings g--d are provided in the member 49-c and these openings are so placed that when the member t1 is moving in one direction the openings iS- d will be closed by means of the shoulder E3-a, thereby preventing iiuid from flowing through the openmgs.

When, however, the member l1 is moving in the opposite direction, the member lis-c will assume a position that a portion thereof will abut the shoulder iii-'b and the openings i5-d will be so positioned that iiuid may flow therethrough.

The object of this dash-pot is that upon acceleration of the engine, the member 41 will be pulling against a partial vacuum below the dash or plunger. `This creates a greater pull across the jet openings of the nozzle and gives a richer mixture.

This result is accomplished because if the Valve 2| is permitted to drop back without the use of the dash pot then there would be no excess vacuum or suction to pull the gas across the jet into the venturi and into theV engine. The object of the dash pot or the partial vacuum below the Adash pot is that the valve 2| will be retarded in its dropping movement and in that retarding movement the vacuum is increased across the jet, which results in a richer mixture.

On the down stroke of the member 48, when cie-accelerating, the fluid belowY the plunger will be by-passed through the openings iS-d, thereby providing for a quick return movement.

The Weight 1 is connected by means of a link 5|! totheend 5| of the valve 2| and tends normal- Y 1y to close the valve. Connected to the member 41 preferably at the upper end thereof, is a cross bar or rod 52 that extends beyond the side of the member, and passing through the member 52 is a bar or rod 53 to one end of which is detachably connected the valve 46. This connection may be formed in any suitable manner such as by means of L-shaped clip members 54 secured to the rod 53 by means of screws 55, the horizontal portions of the members 5a projecting beneath and being spaced from the end of the rod 53 and bifurcated so as to enter a slot 56 in the end of the valve it. The upper end of the rod 53 is preferably threaded as at 51, and a nut or collar 55 is threaded thereupon for adjustably connecting the rod 53 with the cross bar or member 52.

The normal tendency of the weight 61 is to close the valve 2| but when suction is created in the engine manifold through the outlet openings I1 the valve 2| will be opened against the stress of the weight and to a distance proportionate to the amount of suction created, that is, whether the engine is idling or running at full speed. The opening of the valve 2| will correspondingly adjust the valve 6 and anymovement of the valve 2| will control the opening and closing movement of the valve 45;

The member M is provided with an open peripheral groove 51 having openings 58 in the bottom thereof that form communication between the opening e5 and the groove so that any fuel owing through the pipe or tube 5S will enter the groove 51 through the openings 58 to be delivered into the chamber 59.

A plug or screw 5| forms'a closure for the `va1ve member 64 projects. of'which is housed within the valve member 64 `ing or passage 62. 4the chamber 89 beneath the closure member E l.

chamber Y6|] and is provided with a corneal opening 62 into which a conical extremity 63 of a A spring 65, one end and the other end of which abuts a screw plug 6E, tends normally to move the valve 64'and the conical extremity 63 in a direction to close the open- The pipe 59 discharges into A member 61 sliding in a suitable guide or cas- -ing is adapted at its lower end to abut the extremity of the conical portion `63 of the valve member 64. The other end of the member 61 is reduced as at 68 to form a shoulder 69 and a coil spring 10 encompasses the reduced portion 68 with one end abutting the shoulder 69. The otherend of the spring abutsl a pin or member 1| and the stress of the spring 10 tends normally to move the member 61 in a direction to unseat the valve 64-63 to permit fuel to flow through the opening 62.

When, however, suction is created in the engine manifold it will be manifested upon the 'member 61 which serves as a piston, to raise the latter against the stress of the spring 19 and thereby permit the valve 64--63 to be seated by the spring 65. This suction is manifested upon themember 61 through a passageway 12 which has communication with a chamber 13 in which the member 61 operatesI and also with the `outlet opening |1 on the suction side of the throttle valve 28.

v7Therefore, it will be manifest that when the throttle valve 28 is wide open the suction through the passage 12 will be less than the suction in the said passage when the valve 29 is closed orvin a partially closed position.

When the engine is idling or running at a low speed, an additional supply of fuel through the member when the throttle valve 20 is closed. As

vthe suction in the passage 12 decreases the spring 19 moves the member 61 to open the'valve 63-64 and an extra amount of fuel will then'be supplied'from the reservoir 38 through a passage 14 (see particularly Figure 7) through the valve opening 62 into the chamber 69 and will flow through the passage 59 (see also Figure 1) into the passage 51 in the member 44, to be delivered through the openings 58 and thence through the opening 45 into the passage 39.

' In order to prevent the fuel from being drawn up by suction in the passage 12 and chamber 13, between the member 61 and the wall of the charnber, there may be provided a cut away portion in the periphery of the member 51, which, when the member 61 is raised under the inuenc'e of suction will be in register with a vent opening 16, thereby breaking the suction.

A second and different kind of fuel, such for instance as kerosene or other low grade fuel, may also be supplied to the nozzle from a tank 11-A, and to that end there is provided a valve 11 and a supplemental chamber 18 which latter is provided with a closure member 19 having an opening 89 therethrough forming a communication between the reservoir and the chamber. A valve 8|, preferably tapered to kco-operate with the opening 8|! in the member 19, is provided for controlling such opening. This valve 8| is connected by means of connecting members 82, preferably similar to the members 54, to a rod or member'83. The upper extremity of this member 83 is preferably provided with screw threads 84 to receive a nut or collar 85. The end of the bar 83 passes through the member 52 and isI connected thereto in a manner similar to the manner in which the bar 53 is connected.

With this construction it will be manifest that as the valve 2| swings about its pivot 22 and the member 52 is raised and lowered, the valve 8| will be moved through the opening 89, to vary the size of the latter and thereby meter or control the supply of fuel from the reservoir 11a into the supplemental chamber 18v through the opening 80.

Leading from the supplemental chamber 18 is a pipe or passage 86 which discharges into a valve chamber 81. The bottom of the valve chamber is provided with an opening 88 (see particularly Figure '7) which has communication with a chamber 89. A valve S8 is arranged in the valve chamber 81' and is provided with a tapered or conical extremity 9| projecting into and operating through the opening 88 to control the latter.

A spring 82 tends normally to seat the valve 9| to close the opening 88, the Valve preferably being hollow, one end of the spring resting against a shoulder or abutment in the valve and the other end of the spring resting against a nut or collar 93 which forms a closure for the valve chamber 81. Obviously by adjusting the nut or collar 93 the stress of the spring 92 may be varied.

Connected with the valve 98-9I is a rod 94 by means of which the position of the valve may be varied and controlled by the operator. Any suitable means (not shown) arranged in a convenient position for the operator may be provided for actuating the rod 94 to'control the valve 98-9|.

Leading from the tank or reservoir 38 is a pipe or passage 95 (see particularly Figures 4, 5 and 7) which discharges into a valve chamber 96 that is arranged below the valve chamber 81 and is separated from the valve chamber 31 by means of the chamber 89. The wall 91 of the valve chamber 96 is provided with a conical opening 98 forming communication between chambers 95 and 89. A valve 99 having a tapered extremity |89 is provided to control the opening 98. An extension |8| is arranged on the end of the conical portion |99 and is in alinement with and adapted to abut the extremity of the tapered portion 9| of the valve 98. A spring |82 tends normally to seat the valve 99 to close the opening 98 and this valve normally closes said opening 88. ,The valve 99 is preferably hollow and'one end of the spring is seated in the valve and abuts a shoulder. The other end of the spring is preferably seated in a cap |03'. l

The valve Sile-|88 is adapted to be unseated against the stress of the spring |82 by pressure exerted against the extremity of the extension Il by the tapered portionV SI of the valve 99 when the latter is moved into a closing position by the actuation of the rod 84. This will shut off the supply of fuel through the pipe or passage 86 and will permit the supply of fuel from the pipe or passage 95 into the valve chamber 95 to flow through the opening 98 into the chamber 89.y

It is of course to be understood that the construction of the valves Sil-9| and ilslull issuch that while they will control the respective discharge outlets, they will not interfere with the flowing of ie respective fuels through such outlets when the respective valves are open.

The chamber E9 is provided with a discharge outlet opening li to which is connected a passage |35 that discharges into a heating chamber |03, (see particularly Figures l and 4). This chamber Kili may be of any desired size but is preferably comparatively small so as not to contain any great amount of fuel at any one time. The size of the chamber, however, may be varied as desired.

able connection |33, one end of a pipe H9 is' connected. The pipe Hl) is preferably located within the mixing chamber i9 and the other end thereof discharges into the channel 32 in the mixing nozzle so that fuel supplied through the pipe H9 to the nozzle will be delivered into the f channel 32 of the nozzle while fuel supplied throughY the pipe 42 will be delivered into the channel 3| of the nozzle. i

Both of the fuels are entrained through the nozzle by suction and the supply of fuel from I the tank 'lla is metered by the valve 8| while a portion only of the fuel from the tank 38 is metered by the valve 53. When the engine is operating with the throttle valve 25 wide open, as shown in Figure 1, engine suction will swing the valve 2| to the position shown lin Figure 1, land will raise the Weightedrmember il as Well as the bars or rods 53-83 connected to the valves lili- 3| and position the valves to supply the fuel in the proportions commensurate with the supply of air drawn through the carburetor. When the throttle valve 2li is wide open the valve SLi-63 will also be open for the reason that the spring 'lil will overcome the suction created in the chamber 'I3 upon the member El and cause the member to engage the extremity t3 of the valve Eil and unseat it against the stress of the spring 65, thereby admitting `a larger amount of fuel.

When, however, the throttle valve 2i! is closed or partially closed, the suction in the passage 'l2 will be increased and this will be manifested upon the member 61 to raise the latter and overcome the stress of the spring lil so as to permit the Valve Eid-53 to be seated, thereby closing the opening e2 or reduce the size of the opening according to the position of the member 6l.

With this construction it will be manifest that Y the amount of fuel supplied will be controlled by engine suction.

Should the valves gil-3| be positioned as shown in Figure 7, the valve SQ-lilfl will be open and fuel from the reservoir 38 will be supplied through the passage 95 into the Valve chamber 9B to be discharged into the pipe or passage |66 r to be delivered into the chamber |553 and from thence through the pipe lli! into channel 32 of the nozzle.

With the valve Slg-|90 thus open, a single fuel will be supplied to the nozzle. Y

This condition may exist upon starting of the engine. After the engine has been started and it is desired to shift to another'kind of fuel and to shut off a portion of supply of the first fuel to the nozzle and from the channel 32', the rod or member 9s is actuated so as to move the valve Qil--iiV in a position to open the passage S8 to permit another kind of fuel to flow into the chamber It from where it will be delivered from the pipe Htl to the channel 32, at the same time permit the valve SS-lll to close under the influence of the spring |32 end thereby shut of! the supply of fuel from the tank or reservoir 38 to Ythe channel 32.

At the same time, however, fuel from the tank or reservoir 33 will be delivered through the` pipe l2 to the channel 3|.

Under these conditions it will be manifest that there will be rtwo different kinds of fuel being supplied to the chambers'in the nozzle, one on one side and the other on the other side, but as these two different fuelswill be entrained into the mixing tube 26 through the passages 29 by atomization they will commingle and will be delivered into the mixing chamber EQ with the air discharged into the nozzle.

It will therefore be manifest that with the present construction it is possible to operate the engine with either one kind of fuel alone or a mixture of two diiferent kinds of fuel.

This Will reduce the expense of operating the engine as the engine may be started to operate on one of the fuels andthen a portion of the supply of such fuel eut oif, and a less expensive fuel supplied in lieu of the cut off portion and the two fuels will commingle.

If desired, :and for the purpose of operating as a choke to start the engine, any suitable means may be provided, under ther control of the operator, and located in -a suitable or convenient position for maintaining the valve 2| Vagainst opening under the suction of the engine, while the engine is starting. Any suitable means for accomplishing this result may be provided.

A simple and effective means, however, embodies a lmember (see particularly Figure 1) which is mounted in a suitable bearing I2 to contact with the extension 5| on the valve 2| so as to prevent the valve 2| from swinging about its pivot 22.V This member Ill may be operated in any suitable manner (not shown) and when desired may be withdrawn sov that it will not interfere with the swinging of the valve 2| about its pivot 22 under the iniluence of engine suction thereupon.

While the preferred form of the invention has been herein shown and described, it is to be understood that various changes may be made in the ldetails of construction and in the combination and arrangement cf the several parts, Within the scope of the claims, without departing from the spirit of this invention.

What is claimed as new is: Y

l. In a carburetor a fuel nozzle, two sources of supply of different fuels, metering valves individual to the supplies for metering the fuels to the nozzle. a counter-balanced air supply control valve common to and connected with said metering valves for operating them.'t-vo different connections between one of the sources of fuel supply andthe said nozzle, `valves individual to said connections for controlling the passage of fuel therethrough, and a connection between the other of the sources of fuel supply and the said nozzle, a portion of the last said connection embodying a portion of one ofy the first said connections, whereby the valve in the latter will operate to control a supply of fuel to the nozzle from both of said sources of fuel supply.

2. In a carburetor a fuel nozzle, two sources of supply of different fuels, metering Valves individual to the supplies for metering the fuels to the nozzle, automatically operating means common to and connected with both of said metering valves for simultaneously operating them, two different connections between one of the sources of` fuel supply and the said nozzle, Valves individual to said connections for controlling the passage of fuel therethrough, and a connection between the other of said sources of fuel supply and said nozzle, a portion of the last said connection embodying a portion of one of the first said connections, whereby the Valve in the latter will operate to control a supply of fuel to the nozzle from both of said sources of fuel supply.

3. In a carburetor a fuel nozzle, two sources of supply of different fuels, metering Valves individual to the supplies for metering the fuels to the nozzle, a counter-balanced air supply control valve common to and connected with said metering valves for operating them, two different connections between one of the sources of fuel supply and the said nozzle, Valves individual to said connections for controlling the passage of fuel therethrough, a connection between the other of the sources of fuel supply and the said nozzle, a portion of the last said connection yembodying a portion of one of the first said connections, whereby the valve in the latter will operate to control a supply of fuel to the nozzle from both of said sources of fuel supply, whereby an additional amount of fuel may be supplied to the nozzle from one of said sources of supply, and additional means influenced by engine suction for controlling the last said means.

4. In a carburetor a fuel nozzle, two sources of supply of different fuels, metering Valves individual to the supplies for metering the fuels to the nozzle, means connected to both of said metering valves for operating them, two different connections between one of the sources of fuel supply and the said nozzle, valves individual to said connections for controlling the passage of fuel therethrough, a connection between the other of the sources of fuel supply and the said nozzle, a portion of the last said connection ernbodying a portion of one of the first said connestions, whereby the Valve in the latter will operate to control a supply of fuel to the nozzle from both of said sources of fuel supply, and a heater constituting a portion of one of the said connections between the nozzle and one of said sources of supply.

WILLIAM C. DUNN.V 

